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The three‐dimensional Weather Research and Forecasting (WRF) model is used to conduct sensitivity experiments of Typhoon Fitow in 2013 during its landfall. Surface rainfall and heat budgets as well as the vertical profiles of stability and vertical velocity are analyzed to examine physical processes responsible for radiative effects on rainfall. The inclusion of radiative effects of liquid clouds suppresses radiative cooling in liquid cloud layers via reducing outgoing radiation to ice cloud layers, whereas it enhances radiative cooling in ice cloud layers through trapping less radiation from liquid cloud layers. The enhanced radiative cooling decreases from ice cloud layers to liquid cloud layers. The suppressed stability and vertical mass convergence increase. Thus, heat divergence is weakened to warm the atmosphere, which reduces net condensation and rainfall. The inclusion of radiative effects of ice clouds suppressed radiative cooling by reducing outgoing radiation. The suppressed radiative cooling reduces from ice cloud layers to liquid cloud layers, and the suppressed instability and vertical mass convergence decrease when radiative effects of liquid clouds are present. As a result, heat divergence is strengthened to cool the atmosphere, which increases net condensation and rainfall. The suppressed radiative cooling increases temperature and reduces net condensation and rainfall when radiative effects of liquid clouds are absent.

A case study of a convection initiation (CI) event involving a mesoscale gravity wave is presented. This severe convection event occurred in east China on 5 June 2009. High-frequency automatic weather station (AWS) data, visible satellite data, and Doppler radar data were combined to depict the features of the gravity wave and the development of several convection centers. The gravity wave was manifested by a surface pressure dip and surface wind shift propagating westward away from the early convection. The pressure dip propagated at a speed of >30 m s−1, which is comparable with that in previous observational studies of convectively generated gravity waves. A special focus is on the initiation of a deep convection cell in Anhui Province, which resulted in 25 deaths. Surface observations showed two precursors before CI, including a convergence line and wind shift at the eastern end of the convergence line. High-resolution numerical simulations with the Weather Research and Forecasting (WRF) Model were used to examine the structure of the gravity waves and forecast CI processes. The model reproduced the observed features of the gravity wave and the precursors before CI. Three-dimensional model results showed that CI occurred at the intersection between a convergence line and the gravity wave. The relationships between the wind shift and the pressure drop are consistent with polarization relation in ducted gravity waves. As the updraft of the gravity wave intersected with the convergence line, the low-level updraft strengthened and led to CI. The gravity wave, which had stronger updraft than downdraft, suggested a positive contribution to CI.

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A new convective-stratiform rainfall separation scheme is developed through combination of rain types separated by surface rainfall budget using a cloud-resolving model simulation data during TOGA COARE. Three rain types associated with vapor convergence, upward motions throughout the troposphere, and dominant liquid microphysical processes form convective rainfall. Maximum convective rainfall requires precipitation efficiency of 100%, but it is not associated with maximum vapor convergence. Vapor and hydrometeor convergences contribute about 40% to maximum rainfall, respectively. Four rain types associated largely with hydrometeor convergence, upward motions in the upper troposphere, and dominant ice microphysical processes form stratiform rainfall.